The main objectives being considered in these projects are: To determine the mechanisms of control of hemoglobin synthesis which produce the wide variability of hemoglogin S concentrations in individuals with different genetic and environmental backgrounds. To determine the incidence of hearing loss in sickle cell patients; establish clinical audiologic and pathologic correlation in the disease; assess possible ototoxic effects of medication used in treatment; provide definitive diagnosis and therapeutic facilities for hard-of-hearing. Utilizing a set of instruments developed as a pilot study, a full survey will be conducted in the black population of the Chicago Standard Metropolitan Statistical Area to determine and evaluate information in three general areas: (1) knowledgeability of sickle cell trait and disease, (2) utilization of tests for sickle cell trait and (3) attitudes and opinions of individuals, segments and the total population regarding current impressions, issues, anxieties and information related to sickle cell trait and disease. A structured questionnaire will be administered by a group of trained interviewers to a statistical probability sample of households in the Chicago black community. Additionally, a group of persons constituting leadership in the Chicago black community will be surveyed, and a sample of households in each of which at least one person has been diagnosed with sickle cell disease. The Westside Health Planning Organization, which is a community component of this Sickle Center, will conduct a community education program in the target area.